Scientists coax skin cells to behave like muscle cells

Washington, May 6 (IANS) Scientists have now shown that skin cells can be coaxed to behave like muscle cells and muscle cells like skin cells. The fickleness of the cells, and the relative ease with which they make the switch, provide a glimpse into the genetic reprogramming that must occur for a cell to become something it’s not.

“We’d all like to understand what happens inside the black box (cell),” said Helen Blau, professor and member of Stanford University’s Stem Cell Biology and Regenerative Medicine Institute and co-author of a new study on the subject.

Harnessing these genetic makeovers will allow scientists to better understand how to induce specialised adult cells to revert to a stem-cell-like state in a process called induced pluripotency (iPS).

But Blau’s experiments suggest an intriguing alternative to iPS: that of enticing specialised adult cells to switch identities without requiring a dip into the stem cell pool.

Blau, who heads the Baxter Lab at Stanford University and her lab members fused mouse muscle cells with human skin cells, to create hybrids called heterokaryons.

In heterokaryons, the nuclei of each cell type (containing DNA and RNA, responsible for growth and reproduction) remains distinct, and the influence of one on the nature of the other can be clearly distinguished.

They then examined the hybrids to see if they began to look and act more like muscle cells, skin cells or something in between.

The researchers use species-specific differences to track the unique gene-expression profiles of each cell type.

They found that if the muscle cell nuclei outnumbered the skin cell nuclei, the skin nuclei began to express muscle-specific genes within a few hours of fusion.

When the skin cell nuclei were more numerous, the muscle cell nuclei switched to express skin-specific genes. What’s more, the heterokaryons themselves assumed the morphology of the ruling cell type - flat and roundish like skin cells or long and skinny like muscle cells.

“We were especially pleased to see that the muscle cells could begin to act like skin,” said Blau, according to a Stanford release.